Residents braced for more flooding as deadly tropical storm heads their way after remaining over Texas for days.

Western Louisiana residents are bracing for more wind and water as Tropical Storm Harvey headed their way after dumping record rainfall on Texas.

National Weather Service meteorologists expect the deadly storm to make another landfall early on Wednesday in southwestern Louisiana, after it remained over Texas for days before moving back into the Gulf of Mexico.

Forecasters said another 13 to 25cm of rain could fall in western Louisiana.

"We are starting to get down to the end of the tunnel of all this rain," Roger Erickson, meteorologist, said.

Erickson warned that some coastal rivers would not be able to drain effectively because Harvey's winds were pushing in a storm surge, aggravating flooding in areas already drenched by more than 51cm of rain.

John Bel Edwards, Louisiana governor, urged people to remain alert but said the state is responding well to less severe conditions in its own borders.

"You never know what Mother Nature is going to throw at us, but with the people in this room, I'm confident we can handle it," he told local and state officials during a visit on Tuesday to Lake Charles, which is near the Texas border.

Edwards said Louisiana also has offered to shelter storm victims from Texas. He said he expected Texas officials to decide within 48 hours whether to accept the offer.

Harvey's devastating flooding brought back tough memories in New Orleans as Tuesday marked the 12th anniversary of Hurricane Katrina.

Mayor Mitch Landrieu opened his Tuesday news conference with a moment of silence for Katrina victims and words of support for Harvey's victims in Texas and southwest Louisiana.

Landrieu urged residents to stay home on Tuesday because of the threat of potential high water.

Some New Orleans neighbourhoods flooded earlier this month during a deluge that exposed problems with the city's pump and drainage system. On Tuesday, rains flooded a few of the city's streets, but not to the same extent.

New Orleans officials planned to reopen government buildings and public schools on Wednesday, a day after they were shut down amid fears of flooding rain from Harvey.

"The weather outlook got a little bit better for us," Landrieu said. He cautioned, however, that a change in the forecast could mean a change in plans.

About 500 people were evacuated in southwest Louisiana's most populous parish early on Tuesday, as a heavy band of rain pushed waterways out of their banks, Tom Hoefer, Calcasieu parish spokesman, said.

Flooded roads

Hoefer said as many as 5,000 parish residents were affected by the flooding, but not all of those people have flooded homes. Some are just cut off by flooded roads.

Evacuations continued on Tuesday in some rural areas outside Lake Charles, with authorities working to empty a flood-prone subdivision near the town of Iowa. Officials in Acadia Parish advised residents near the Mermentau River and Bayou Nezpique to leave.

Family members and authorities in Texas have reported at least 18 deaths from the storm.

No Harvey-related deaths were immediately reported in Louisiana, according to a spokesman for Edwards.